*** 1978 ATC 90 "3D" Dickson Design & Development Mono Frame ***

[Joseph Farrow]

Hey guys wanted to share me and my brothers third installment of Old School period correct ATC 90-110 trikes. As you may know when I came to 3WW it was to have a resource for finding and locating bikes and parts for the ATC90-110. Our goal was to build two race bikes and two dune bikes exactly as they were back in the day. The 90-110's had so many hipo aftermarket parts available due to the fact that for the first 10 years it was the only option when it came to trikes. It was a special time for us growing up in the hayday.

This is Judson's "Race Bike" build. We always wanted a fully suspended 90-110 race bike. They were short lived due to the fact that about the time they began to catch on in popularity over the hard tail framed bikes Honda released the ATC250R in 1981. When that happened it pretty much killed everything 90-110.
With that being said we still have always wanted one. They are very rare, especially the 3D version. It was specifically produced for racing. Some of the other versions from different manufactures were more for recreational use.

Dickson Design & Developement (3D) was located in Nation City California and headed up by the one and only Bob Dickson!
This is from an article in the Summer 1980 issue of 3Wheeling Magazine.

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The article states that the mono-shock design wasnt the first attempt to install rear suspension on a three wheeler, it was the first to be put into production.

As in previous build treads I will first start with pics of the finished product then break it down into Chasis and Engine.
This bike is also inspired by our last ATC110 race bike "The Blue Goose".

Here is "The Blue Goose II"

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I think it came out Awesome! I have yet to ride it but Judson says it Hauls trailprotrailprotrailprotrailprotrailpro.

[Joseph Farrow]

Here are some of the specifics on the Chasis.

Let's start at the front of the Bike.

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It sports Vintage Grab-On grips with Renthal Bars and MX Cross Bar Pad. Front brakes are a super cool NOS Hurst Airheart disc brake set up. Twist trottle is a Vintage Magura qtr turn with a NOS BAPP Mikuni Cable.

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Front triples are aftermarket with 31mm tubes. Front tire is a NOS Ohtsu 20x7x8 Odyssey Front Tire.

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Gas tank is from a 1979 XL 250. Rear fenders are Aftermarket and are unsure of mfg.
Rear tires are NOS Carlisle Turf Savers 18x9.5x8 with aftermarket axle extenders and 32T Rear Sprocket.

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Aftermarket Cleated Foot Pegs as well as a HD Rear Axle Carrier.

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Forgot to mention....I did the Paint on this Bike!

Stay tuned for the Engine Specs next!

[Joseph Farrow]

Okay Engine Specs!

1978 ATC 90 Motor built to 180cc.
Head ported and polished with lightened and polished valves.
Lightened and Polished Rocker Arms.
Vintage 90 Pauter Cylinder with 6mm spacer for Long Rod Stroker Crank.
Modified 61.75mm Honda CB 750 Piston
110-61mm Helm & Son Stroker Crank
Oil Bypass System
Lightened Flywheel

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Quick Change Sprocket Assembly
Manual Clutch
Vented Helm & Son Dip Stick
PK Intake with 26mm Mikuni Carb and K&N Filter
NOS BAPP Large Pull Start Handle
Custom Bassani Pipe (Modified to fit Mono Frame)

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Again wanted to share. I think this is a really neat bike. It is just about as Bad a ATC90 you could build for the track back in the Day!
Would also like to Thank several members here on this board for their help in making this bike happen. Without you guys it wouldn't have been possible.

Stay tuned for my final installment of our 90-110's.....The Team BAPP Replica Bike Build coming soon.

[Ghostv2]

Your builds are always an inspiration to get my semi suspended pauter finished. But finding anything 90/110 racing related on the east coast is hard.

I wish we could see more bikes like this on the track at TF every year. By far my favorite builds.

[pipeline triker]

Very nice, love the 90 builds.

[shortline10]

Wow Joseph , you and Judson did a great job !

[ctk]

Great pics, How would this trike compare to a 1983-19&5 Honda 200x, in relation to engine power and suspension and turning. On a mx and flat track

[Ghostv2]

Might be a stupid question but I'm no expert on engines. Anyways, do you NEED to do the oil bypass for the cb pistons because the cylinders are basically bored to their maximum ability and re-sleeved? I don't recall ever seeing that and I've talked to veilmonkey in the past about buying a NOS CB piston kit (before the fire and everything else happened) for my build. Or does this just help with cooling and eliminate the need to tap in for a radiated oil cooler? Because I know these engines get HOT with that much work done.

[HairyJR]

Another great Farrow brothers creation, love the blue color. Lots of vintage parts. I don't believe ever seeing anyone race one that nice back in the day.

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[Jwheeler]

Great job as always !!!!!!!!!!!! Judson has sent me pic's as it has been built. I need to get mine done now.That way we can tear it up in dunes together !

[yaegerb]

Good heavens, that is sick :drool:

It's about time for another build thread to go into top tier. I think this one deserves it. Lemme see about getting it moved.

[big specht]

Looking good as usual you guys do a good job. The cb piston peeked my interest what all is involved in using those pistons?

[Aulbaugh]

Amazing work! That is a head turner. It's crazy to think those little guys were used to race.

[Joseph Farrow]

Great pics, How would this trike compare to a 1983-19&5 Honda 200x, in relation to engine power and suspension and turning. On a mx and flat track

Chris to answer your question the 180's ran very well. In my opinion they were pretty equal to a built 200x when it came to power to weight ratio. These bikes are alot smaller and lighter than the 200x. My brother and I actually raced against 200x's and 250r's on our 180's and did very well. I think a lot of it had to do with riding ability but compared to a stock 90-110 you would be very supprised at how fast and how much torq these thing put out.

[Joseph Farrow]

Might be a stupid question but I'm no expert on engines. Anyways, do you NEED to do the oil bypass for the cb pistons because the cylinders are basically bored to their maximum ability and re-sleeved? I don't recall ever seeing that and I've talked to veilmonkey in the past about buying a NOS CB piston kit (before the fire and everything else happened) for my build. Or does this just help with cooling and eliminate the need to tap in for a radiated oil cooler? Because I know these engines get HOT with that much work done.

The latter is correct. It helps with cooling as well you can see you are getting oil to the head. These engines do run very hot and the oil comes from the oil pump and runs up the cylinder stud to the top of the engine. You could still use a finned oil cooler with this set up if you like for extra cooling.
Check out where the oil gallery runs in this "Cheater Cylinder"....the old sleeve is bored completely out and a new larger one is pressed in. The out side of the sleeve is actually part of the oil gallery. lol

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[Joseph Farrow]

Looking good as usual you guys do a good job. The cb piston peeked my interest what all is involved in using those pistons?

It's not an easy thing to do. First you have to source one of the three options below. An oversize sleeve cylinder.

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To be able to run the oversized sleeve cylinder you will have to have your center cases bored to accept the larger outer diameter of the sleeve.

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Then you have to have the CB piston machined to work with the correct deck height, valve pockets and crank.
This first pic is a side by side comparison of a stock CB750 piston and one after it has been machined.

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This is the reasons I like the 90-110's so much. There were so many mods you could do to these machines to make them not only look good but kick trailprotrailprotrailprotrailprotrailpro as well!

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As the old saying goes....."Speed Cost - How Fast Do You Want To Go???" lol

[Ghostv2]

The latter is correct. It helps with cooling as well you can see you are getting oil to the head. These engines do run very hot and the oil comes from the oil pump and runs up the cylinder stud to the top of the engine. You could still use a finned oil cooler with this set up if you like for extra cooling.
Check out where the oil gallery runs in this "Cheater Cylinder"....the old sleeve is bored completely out and a new larger one is pressed in. The out side of the sleeve is actually part of the oil gallery. lol

That's what I thought. I guess I'll have to pick your brain when I move on to engine work with my build. I'm still sourcing parts. Right now I only have bolt on mods. Powroll intake, vm26 carb, cobra pipe, low-mid cam, all on stock bore. You'd be surprised how much it wakes this thing up even with a stock piston. It's a wheelie machine with the tucker rocky front suspension kit and the pauter +2 frame.

Feel free to send me a pm now and then with extra parts left over from these builds. ;)
People on eBay try to rob you with their prices for hop up parts most of the time.

[big specht]

Thanks that's nice to know cause I have a 70 that I built along time ago with a used 110 big al's big bore piston(I think) and a custom la sleeve sleeve. And it's starting to burn some oil and I wasn't sure what to do about a piston. So thanks for the info. Is there any certain year CB750 to get pistons from?

[Dirty200]

wow! freaking beaut

[Dirtcrasher]

That came out awesome, thanks for sharing!!!!

[Ol Deuce]

Joseph your 3D Project turned out Perfect ..........Ol Deuce

[Joseph Farrow]

Thanks that's nice to know cause I have a 70 that I built along time ago with a used 110 big al's big bore piston(I think) and a custom la sleeve sleeve. And it's starting to burn some oil and I wasn't sure what to do about a piston. So thanks for the info. Is there any certain year CB750 to get pistons from?

It needs to be for the early single valve CB750. Honda CB750K-K6 (1969-76)

[HondaRidr]

Awesome build. Those old racers are so cool!

Sent from my SM-G930T using Tapatalk

[Ghostv2]

So are those Douglas 8x8 wheels with the turf tamers squeezed on? I wanna try and run along the same tire setup with mine. I'm not sure how jumping will go on a solid frame with those kinda tires though. I mean it's not like you're getting huge air anyways. But still. I need to find or make some cleated pegs though. But I'd like to find similar ones to yours. The bar and mount looks way more solid.

Also how's your speed with the 32T sprocket and the smaller tires? I'm sure power and acceleration is amazing, but I'm not sure how it would match in speed. Is the sprocket NOS aftermarket or did you have it made? You can only get like 48-51T available new anymore.

Hope you don't mind all the random questions lol. Just trying to get my build done right the first time. Gotta ask all the questions I can to a person who knows about the 90/110s the most while I have your attention lol. Like you, these are my favorite builds for all the same reasons. There was so much you could do to these and so much available. Too bad nobody puts time into repop'ing these old race parts like they do with the 250r's.

[90crazy]

Awesome job! Museum quality for sure.:w00t:

[ironchop]

Awesome build....Id love to hang out in y`alls garage over a weekend.

[Ghostv2]

Awesome build....Id love to hang out in y`alls garage over a weekend.

I second that. I'll put my sleeping bag right next to the 90's.

[Joseph Farrow]

So are those Douglas 8x8 wheels with the turf tamers squeezed on? I wanna try and run along the same tire setup with mine. I'm not sure how jumping will go on a solid frame with those kinda tires though. I mean it's not like you're getting huge air anyways. But still. I need to find or make some cleated pegs though. But I'd like to find similar ones to yours. The bar and mount looks way more solid.

Also how's your speed with the 32T sprocket and the smaller tires? I'm sure power and acceleration is amazing, but I'm not sure how it would match in speed. Is the sprocket NOS aftermarket or did you have it made? You can only get like 48-51T available new anymore.

Hope you don't mind all the random questions lol. Just trying to get my build done right the first time. Gotta ask all the questions I can to a person who knows about the 90/110s the most while I have your attention lol. Like you, these are my favorite builds for all the same reasons. There was so much you could do to these and so much available. Too bad nobody puts time into repop'ing these old race parts like they do with the 250r's.

Yes those are Douglas 8x8 wheels. The tires work excellent for most tracks. We ran them on flat track, TT and MX. As far as jumping, it's like jumping on anyother hard tail. Kind of like riding a bicycle. You can jump things for example a double and as long as you land on the down slope you're good. lol

When Judson broke in the bike he had a 11-49 sprocket combo. With the smaller diameter tires it was all low end with no top end. He switched out to a 12-32 and it made all the difference in the world. It still has enough torque to wheelie in every gear and will pull way out for speed. The 32 tooth rear sprocket was special order. A friend had a batch made and we grabbed a few. As far as the cleated foot pegs you can probably find a set without much trouble.

[Joseph Farrow]

https://www.youtube.com/watch?v=BlWDV-CZllw

Here is some 90-110 Race Action. Sorry for such a short vid. My phone would only let me do so much.....
In this vid I pull the hole shot and Jud is in Second. I think he gets by before the end of the race. In the main I pull the hole shot and end up winning. Jud gets tangled up with some other riders at the beginning and has to make his way through the pack. He ends up second.

[Ghostv2]

Those things look like 200x's scootin' around the track. That's crazy!

[yaegerb]

Good Morning Joe,
FYI, we are moving this thread to top tier build today. Just wanted to let everyone know that this will be in that forum section.

Again, great job! WE NEED MORE BUILDS LIKE THIS!

[Joseph Farrow]

https://www.youtube.com/watch?v=JQK5ILgO0BM
Those things look like 200x's scootin' around the track. That's crazy!

Here is the start to the Main. Again sorry for short vid. Jud is in second on the Original "Blue Goose"!
I'm on a friends bike he let us race. It was called "Nightmare" He had a pic painted on the tank with Elmer Fudd shooting the Bird. lol

[taiterator]

You built a real stunner there, nice!!